Altitude And Air Resistance

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 2:57 pm

Here is a thread about Eddy Merckx who smashed the cycling hour record at Mexico City in 1972. "There was some controversy regarding the attempt due to Mexico City's high altitude supposedly providing lower air resistance being an unfair advantage to Merckx." <a href='http://www.thespincycle.com/trips.asp?l ... st_cyclist' target='_blank'>http://www.thespincycle.com/trips.asp?l ... ist</a> As on the bicycle, the erg fan has less resistance at altitude. Hence, as with the bicycle, erg times are faster at altitude than at sea level.

[old] PaulS · Post by **[old] PaulS** » February 18th, 2005, 3:23 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 10:57 AM)</div></td></tr><tr><td class='quote'>As on the bicycle, the erg fan has less resistance at altitude. Hence, as with the bicycle, erg times are faster at altitude than at sea level. </td></tr></table> Ah, once again you try to bring Bizzarro World "facts" in to the Real World. Please just stop! You are stating things as being "matter of fact" when they are no such thing. First of all, the DF calculation takes care of any discrepenacy of having less air resistance and adjusts for that. i.e. DF 110 at sea level = DF 110 at 5000ft altitude. C2 has well established figures (at least well enough for them to adjust for CRASH-B qualifying times) for the differences between sea level races and those done in Denver (Mile High Sprints), and the ones done at altitude are NOT faster. So, while height may have a positive correlation with potential Erg Performance, altitude would possibly be negatively correlated. The decrease in atmospheric pressure at altitude reduces the amount of O2 an athlete has available to utilize so perfomance is hindered, OTOH if on a bicycle, the drag on the athlete is reduced and it could be possible that even though the athlete could not produce as much power, they would not need to, and could cover a given distance more quickly. This would be similar to the lwt Vs hwt rowers on the water, the lwt can not produce as much power as the hwt, but does not have as much drag to overcome due to the displacement of the hull. On water times have very little difference between lwt and hwt, though the hwt's still seem to be the fastest overall.

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 5:51 pm

O2 differences don't affect times that much, IN FIT INDIVIDUALS. Running times are FASTER at altitude up to 800 meters, and close for distances beyond that, for example 10000 meters, and 30 kilometers etc. The C2 "adjusted" times are well BEYOND the difference of even long distance running times. The difference for O2 consumption for a 2k would be practically nil. However, the air resistance reduction is a GREAT AID in overcoming the INERTIA of the fan and, thus, getting faster times at altitude than at sea level. Cyclists are well aware of this advantage as well. There is no question of the advantage of altitude for rowing, in fit individuals. The only question is HOW MUCH this advantage would be.

[old] rjw · Post by **[old] rjw** » February 18th, 2005, 6:28 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 09:51 PM)</div></td></tr><tr><td class='quote'>Running times are FASTER at altitude up to 800 meters, and close for distances beyond that, for example 10000 meters, and 30 kilometers etc. The C2 "adjusted" times are well BEYOND the difference of even long distance running times. The difference for O2 consumption for a 2k would be practically nil. However, the air resistance reduction is a GREAT AID in overcoming the INERTIA of the fan and, thus, getting faster times at altitude than at sea level. Cyclists are well aware of this advantage as well. There is no question of the advantage of altitude for rowing, in fit individuals. The only question is HOW MUCH this advantage would be. </td></tr></table> John, Nice try! The reason cyclist seek out higher altitutes for one-hour records is because the gain in speed due to less air resistance is greater than the loss of performanace due to lower O2 levels. Sililar for running but not to the same degree (over 800 metres). For the erg, a higher eleveation will reduce the drag, all things being equal, for a given damper setting, (but you can achieve this by rowing at a lower drag at sea level). As Paul said, you can't change this because it is hard wired in. For erging, the distance traveled on the slide is too short to take advantage of the lower air resistance. The lack of O2 in the air is a greater detriment than the negligble effect of the lower air resistance moving up and down the rail. Give it a try John. Raoul

[old] ebolton · Post by **[old] ebolton** » February 18th, 2005, 6:42 pm

Cyclist/rower agrees with Raoul and Paul Get Lance Armstrong on the track at Mexico City with a firefighters Scott Airpak, and you would see an unofficial hour record that would amaze. Ed

[old] NavigationHazard · Post by **[old] NavigationHazard** » February 18th, 2005, 6:55 pm

I reserve judgement about longer events, but the positive effect of altitude on lowering sprint times in track is pretty well established -- and marginal. See for example <a href='http://www.sportsci.org/jour/03/jsjrm.htm' target='_blank'>Effects of Wind And Altitude On 110m Hurdle Races</a> The extensive bibliography is a pretty good indicator of research on the topic. The authors of this study reckon that each 625m of altitude improve 110m hurdle performances by 0.03 sec. My understanding of the science however is that for distances greater than +/- 800 meters, performance tends to fall off fairly dramatically. For distance runners, the general point of altitude training is to build up cardiovascular efficiency at lower pressure and oxygen levels in the mountains, then move down close to sea level to compete. The present world record in the 10k, for example, was set in Ostrava (CZ), altitude 256 m, not La Paz (Bolivia), altitude 3700m. I suppose the rowing equivalent of altitude training would be a camp on Lake Titicaca....

[old] PaulS · Post by **[old] PaulS** » February 18th, 2005, 7:38 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 01:51 PM)</div></td></tr><tr><td class='quote'>O2 differences don't affect times that much, IN FIT INDIVIDUALS. Running times are FASTER at altitude up to 800 meters, and close for distances beyond that, for example 10000 meters, and 30 kilometers etc. The C2 "adjusted" times are well BEYOND the difference of even long distance running times. The difference for O2 consumption for a 2k would be practically nil. However, the air resistance reduction is a GREAT AID in overcoming the INERTIA of the fan and, thus, getting faster times at altitude than at sea level. Cyclists are well aware of this advantage as well. There is no question of the advantage of altitude for rowing, in fit individuals. The only question is HOW MUCH this advantage would be. </td></tr></table> Even yelling will not help to validate your ridiculous claims. Then you go on to say "There is no question of the advantage of altitude for rowing, in fit individuals.", yes there is a question, actually two. When? Where? It is also not a matter of "fitness", as that would be a constant as far as an individual was concerned. While we are at it, why not tell us what would happen if Slides were used at altitude? Surely you must have an equally entertaining theory on that.

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 7:49 pm

Yes it is a matter of fitness. For example, if you were to row for an hour at altitude (presuming you can do this at sea level), your time will be much slower -- due to your lack of fitness. The altitude will be a much greater hindrance to your O2 carrying capacity than the average beginning rower, as your fitness is so much less. However, fit rowers, who can easily row for hours and hours every day, will likely have faster times at altitude, due to the decreased air resistance.

[old] PaulS · Post by **[old] PaulS** » February 18th, 2005, 9:15 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 03:49 PM)</div></td></tr><tr><td class='quote'>Yes it is a matter of fitness. For example, if you were to row for an hour at altitude (presuming you can do this at sea level), your time will be much slower -- due to your lack of fitness. The altitude will be a much greater hindrance to your O2 carrying capacity than the average beginning rower, as your fitness is so much less. However, fit rowers, who can easily row for hours and hours every day, will likely have faster times at altitude, due to the decreased air resistance. </td></tr></table> Well, now you have changed to "likely have faster times at altitude", which is still far from being correct, but closer than your earlier assertion. You seem to think that I am less fit than the average beginning rower, where on earth did you come up with that idea? The same place as the rest of your ideas I suppose. We could talk about maximum power output if you like, I was asked to demonstrate how to hit "faster paces" while strapless, during the w/e at CRASH-B's, and I think I illustrated the technique adequately. The witnesses might have another take on that and should feel free to chime in. Finally, the decrease in air resistance is accounted for by the Drag Factor, so unless you are going to also claim that lowering the DF also is a guarantee of faster times, you may want to rethink just a bit. You still have not addressed the fact that being at high altitude makes it more difficult for any individual to maintain workloads that they could sustain at lower altitudes, especially when dealing with maximal aerobic output. Wow, I almost fogot how fun "johnnyball" was. Batter up!

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 9:22 pm

Hi Paul, Realizing your lack of fitness can be a good motivation to improve it. From memory, your PATT percentages are something like: 2k - 86% 10k- 78% h/m- 73% Your percentages decline, by quite a bit, as the distance gets longer.

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 9:24 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(PaulS @ Feb 18 2005, 05:15 PM)</div></td></tr><tr><td class='quote'>Well, now you have changed to "likely have faster times at altitude" </td></tr></table> No, there is no change. The average fit rower can achieve faster times at altitude, period. However, that is no guarantee that just anyone would be faster.

[old] PaulS · Post by **[old] PaulS** » February 18th, 2005, 10:08 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 05:22 PM)</div></td></tr><tr><td class='quote'> From memory, your PATT percentages are something like: 2k - 86% 10k- 78% h/m- 73% Notice the decline as the distance gets longer? And this is no small matter. An 8% drop from 2k to 10k is a major difference, illustrating your gross (pardon the pun) lack of fitness. Even beginning rowers would have a closer percentage than this. </td></tr></table> The value of PATT has never actually been established, and there is no way you can be basing your calculations (and I use the term loosely) on any figures that represent my particular fitness level. I can assure you that I am in the 90th percentile for any distance where more than a recovery day pace has been attempted. Your ignorance, while amusing, is becoming embarassing. Please stop while a newbie might be able to still think you are not a total nutball, or don't. It's a short month, you should not have run out of meds yet. How's the "level rail" Erging going anyhow? You know that's cheating don't you?

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 10:33 pm

The value of PATT is well established as it is based on World Record performances for each age, gender, and weight class. Your PATT percentages are based on the fastest times you have accomplished and entered in the rankings, in the last 3 years.

[old] John Rupp · Post by **[old] John Rupp** » February 18th, 2005, 10:38 pm

Having a level railing is not cheating, as it is not a modification. However, I am using c2's 2% modification, as it is the way they have produced the erg. One of these days I will make adjustable back legs for the railing, so the slope can be changed easily for training purposes.

[old] whp4 · Post by **[old] whp4** » February 19th, 2005, 8:22 am

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'>QUOTE(John Rupp @ Feb 18 2005, 09:51 PM)</div></td></tr><tr><td class='quote'>O2 differences don't affect times that much, IN FIT INDIVIDUALS. Running times are FASTER at altitude up to 800 meters, and close for distances beyond that, for example 10000 meters, and 30 kilometers etc. The C2 "adjusted" times are well BEYOND the difference of even long distance running times. The difference for O2 consumption for a 2k would be practically nil. However, the air resistance reduction is a GREAT AID in overcoming the INERTIA of the fan and, thus, getting faster times at altitude than at sea level. Cyclists are well aware of this advantage as well. There is no question of the advantage of altitude for rowing, in fit individuals. The only question is HOW MUCH this advantage would be. </td></tr></table> Yes, a lower air density makes it easier to spin up the fan. It also means the fan doesn't spin down as quickly -> lower drag factor. You can see this quite easily by pulling one stroke at a pace you can always hit on the first pull, then timing the time it takes for the flywheel to stop spinning. Repeat the experiment, except immediately close the vent after the pull and notice how much longer it takes for the flywheel to stop (assuming you don't have the vent closed all the time). You'll have a different vent setting to get the same drag factor at altitude, but once you hold that drag factor constant, the thinner air will have no impact on the flywheel dynamics. It will have an exceedingly small impact on your moving up and down the rail, just as having a fan blowing on you does. You're not moving through the air anywhere near as fast as a decent runner - let's be generous and say you go the whole length of the slide (call it 2 meters) and rate 42. That's 2*2*42 = 168 meters per minute or somewhat slower than a 9 minute mile pace. We'll make the arithmetic simple and assume that those decent runners are going at a 4:30 mile pace, twice as fast. The power required to overcome the fluid resistance varies with the cube of the speed, so the runners going twice as fast at the same altitude face 8 times the air resistance as your body encounters going along the slide. Going to altitude is a big help to them (same for cyclists) only because they are moving through the air much faster than you are. I just looked at the times of the individuals who qualified at the Mile High Sprints in Denver and their performances down at sea level a few weeks later at the CRASH-B. The funny thing of it is, they were all faster down in the thicker air, opposite of what your theory predicts. One of those individuals (who is in your weight/age/gender category for qualification purposes) rows faster than you do at both 2k and 21k, so I have trouble with "well, he's not a fit individual" as an explanation for this anomaly. Do you have any other explanation? Can you give an example of someone who can row a long aerobic piece faster at altitude? Could you also discuss the effect of ever lower air density on performance? If we put a rowing machine in an altitude simulator and slowly decrease the air pressure, how much faster can we expect the rower to be at an effective altitude of 10,000 feet? 20,000 feet? 50,000 feet?

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